1. Field of the Invention
This invention relates generally to hand propelled carts or trucks, and more particularly to a hand brake apparatus for hand propelled trucks.
2. Brief Description of the Prior Art
Braking systems for carts are known in the art. There are several patents which disclose various hand propelled carts and trucks having hand brakes.
Volkman, U.S. Pat. No. 1,416,427 discloses a hand truck with a brake system utilizing a pawl and ratchet mechanism on the wheels.
Klemm et al, U.S. Pat. No. 3,134,461 discloses brake system for steerable running gear assemblies.
Sanders et al, U.S. Pat. No. 3,174,768 discloses a four wheeled luggage cart with a brake system utilizing a drop rod and notched discs on the wheels.
Honeyman, U.S. Pat. No. 3,276,550 discloses a hand truck having a braking system utilizing a pivoting rod which frictionally engages the wheel surface.
Barron, U.S. Pat. No. 3,422,930 discloses a hand truck with a brake system utilizing a friction strap and brake drums on the wheels.
Malloy, U.S. Pat. No. 3,486,587 discloses a hand truck with a brake system which has pivotal linkage controlled by a hand lever. Friction pads at the end of the linkage contact the wheel surface. The brakes may be applied to each wheel independently or together.
Anderson, U.S. Pat. No. 4,018,449 discloses a shopping cart with a braking system utilizing a spring loaded toggle plate which contacts the wheels. The braking mechanism allows automatic release of the brakes during normal activities with the hands on the handle and will lock when the handle is released.
Boyd, U.S. Pat. No. 4,142,732 discloses a hand truck having a series of pairs of wheels and is capable of climbing stairs. The a hand truck has a brake system utilizing a friction strap and a brake drum on the plate carrying the wheel axles.
The present invention is distinguished over the prior art in general, and these patents in particular by a hand brake apparatus which in one embodiment comprises a singular tubular housing attached to the load supporting frame horizontally between and parallel to the rotational axis of two laterally opposed support wheels having a fixed direction. A pair of opposed extensible wheel engaging members carried within the housing extend outwardly from each end thereof and are provided with a resilient brake disc to engage the sidewall of the stationarily mounted support wheels and thereby prevent rotation of the wheels. A compression spring maintains the extensible wheel engaging members in a normally retracted position spaced inwardly adjacent the wheel sidewall. Alternatively, two smaller housings may be installed adjacent the stationarily mounted wheels and each carries a single extensible wheel engaging member to engage the sidewall of the stationarily mounted support wheels. The extensible members are actuated by a hand grip lever attached to the truck handle.